Science of SUNDIALS!

​For millennia humans have been using Sun and shadow to predict the seasons. "Early farming societies were at the mercy of the seasons. [For] a group of people to sustain a successful farming culture, they needed to come up with accurate ways of predicting when spring would occur (to know when to plant) and when the first frost could be expected (to know when to harvest)." (NASA) Groundhog Day, February 2nd, is a popular tradition whose global legend traverses centuries. It is the day that the Groundhog comes out of his hole after a long winter sleep to look for his shadow. If he sees it, he regards it as an omen of six more weeks of bad weather and returns to his hole. If the day is cloudy and, hence, shadowless, he takes it as a sign of spring and stays above ground. Measuring time is just as important as predicting seasons. Ancient humans used the sun and shadow to mark time. The Egyptians were the first to use sundials. They used a stick or pillar called the gnomon. Time was calculated depending on the length of the shadow. Greeks developed a sundial that would tell time-based on the location of the gnomon's shadow on a disk. For today's "Sci-Fi Friday" students created a paper sundial while they learned about time loops in the classic film, Groundhog Day.